16:3 They came as a group and confronted Moses and Aaron, saying, "You've overstepped yourself. This entire community is holy and God is in their midst. So why do you act like you're running the whole show?"

16:13 Isn't it enough that you yanked us out of a land flowing with milk and honey to kill us in the wilderness? And now you keep trying to boss us around!

If people are not willing to follow and obey the authority you have, they question the authority. But the LORD already gave them a sign of His authority, it's on verse 27: "as they were walking through the Temple," as prophesied in Malachi 3:1

3:1 "Look! I'm sending my messenger on ahead to clear the way for me. Suddenly, out of the blue, the Leader you've been looking for will enter his Temple—yes, the Messenger of the Covenant, the one you've been waiting for. Look! He's on his way!" A Message from the mouth of God-of-the-Angel-Armies.